For your horse’s health and comfort in the trailer, open the vents and windows (with bars and screens safely in place) to allow fresh airflow. Overhead vents provide the best air circulation. There should be one overhead vent for every horse the trailer is built to carry.
Blowing dust, hay, and shavings inside the trailer can cause respiratory distress. Do your best to minimize shavings to just what’s needed, and keep hay confined in small bags. Monitor the temperature often; the heat inside your trailer can build up quickly no matter what the season.
Ventilate your trailer well to help keep your horse breathing easily — and the trailer from getting too hot. When your trailer is in motion, use screens and a fly mask to keep road debris out of your horse’s eyes.